The objective of the present invention is to drastically improve on the traditional prior art apparatus and method of separating comestibles and other product components of differing specific gravity by flotation. When a product such as clam meat and shells are introduced into a flotation tank containing a saline solution of sufficient concentration, the lighter clam meat will float to the surface and can be scooped up while the heavier shells remain at the bottom of the tank. Variations of this procedure are known in the prior art including separator tanks equipped with product infeed and removal conveyors.
The main difficulty with the prior art flotation process is that the salinity concentration of the flotation bath constantly drops and therefore some of the meat or other light product component being harvested sinks to the bottom of the tank and is discarded with the shells or other waste component, resulting in valuable product loss and lessened production. Also, the cost of salt in the prior art method is very high.
The present invention completely eliminates these drawbacks in the prior art by providing a simple and economical fresh water product separator and method of wide versatility in terms of its ability to separate many different types of product components including shellfish and other comestibles. In lieu of a saline bath to effect the separation of lighter product components from heavier components by differential flotation, the present invention utilizes an artificially induced circulation of the fresh water or another fluid in one zone of the apparatus to effect the desired separation of product components having different specific gravities. More particularly, a pumping system induces a current up-flow through one side of a foraminous elevator means for the product causing the lighter product component to rise to the top of and then to overflow a submerged divider and to then settle on the foraminous elevator means on the side thereof remote from the heavier product component which is unable to overflow the top of the submerged divider. The thus separated product components continue to be conveyed upwardly through the fresh water bath beyond the controlled buoyance zone for further washing prior to the discharge of the separated components into separate receivers beyond the top of the elevator means. The process is very efficient and the apparatus used to practice the process is reliable and economical. There is virtually no usable product waste and the necessity for using expensive salt and constantly adjusting salinity is entirely avoided.
A very important aspect of the invention resides in the fact that the product components undergoing separation are able to travel upwardly continuously without interruption while passing through the controlled buoyancy zone and thereafter until the separated components reach the discharge station. It is unnecessary to interrupt continuous product transport through the system while induced flotation separation is being carried out. This renders the process faster and therefore more economical .